1. Field of the Invention
The present invention relates to small wheeled vehicles, carts, or conveyances used primarily for the amusement of their riders.
2. Description of the Related Art
Throughout history, mankind has enjoyed the sensations associated with locomotion provided at least in part by means other than his own legs and feet. Myriad vehicles and conveyances, both wheeled and non-wheeled, both pragmatic and frivolous, powered by gravity, animal, or mechanical means have been devised and enjoyed by people of all ages.
One of the oldest such devices is the simple sled, consisting of two runners which glide on snow or ice, bridged by a platform on which riders are seated or lie prone. The sled, by virtue of its low position relative to the ground, provides an exhilarating sensation of speed to a prone rider, however, its reliance on the presence of snow or ice is a disadvantage where none is available, limiting its usefulness to certain seasons and/or climates. The sled's steering maneuverability is also typically very limited, and its braking capabilities are virtually nil apart from the riders' dragging body parts on the snow or ground.
Wheeled wagons also have a long history as amusement devices, most well-known being perhaps the “Radio Flyer™” type of child's wagon, consisting of four wheels, the front two of which are steerable by means of a handle on an arm linked to their common axle which has a single pivot at its center, and a platform with raised sides on which a child can sit. This type of wagon suffers limitations in maneuverability due to its primitive steering mechanism and relatively long wheelbase (the distance between front and rear axles). It is also not designed for or conducive to prone riding due to its raised sides, and its platform sits fairly high off the ground. Most wagons furthermore are equipped with solid, narrow tires and are therefore better-suited to low-speed rolling on smooth surfaces as opposed to rough terrain. Most wagons do not provide a means of braking, which can present a safety hazard.
Skateboards are immensely popular and highly maneuverable, but require a great deal of skill to ride and are not particularly conducive the prone riding. They also do not have brakes and typically are not well-suited to rough terrain.
Motorized “go-karts” are also popular and can offer great speed, but are relatively complex and expensive, large and heavy, and do not offer a prone riding position. In particular, the braking systems used in motorized go-karts are a source of complexity and expense. The most common systems, in descending order of sophistication, are disc, drum, band, and “scrub” brakes. Of these, only the first two are suitable for front-wheel braking due to the pivoting steering mechanisms of the front wheels, and even these require flexible cables and other elaborate design elements to achieve front wheel braking. Far more common in go-karts, especially less costly ones, is rear-wheel braking, which due to forward weight transfer during deceleration, is less effective than front-wheel braking. Furthermore, rear-wheel braking systems typically require one or more mechanical linkages running from the forward-located operator controls back to the rear wheels, which is problematic if easy folding or collapsing of a vehicle for compact storage or transport is contemplated.
Go-karts typically are not designed for ride height adjustment; they are either designed for low ground clearance for smooth racetrack use, or for high ground clearance for rougher terrain. The steering mechanisms typically used on such vehicles do not lend themselves to easy ride height adjustment because their steering linkages are attached to components whose positions change with ride height.